Andrew Arena, the former chief investigator in the Flint water scandal, says he's confused and bothered by Attorney General Dana Nessel's decision last week to drop all the pending charges against eight defendants in the case and start over again.

"What matters is justice for the people of Flint and they're getting screwed again," Arena said on Charlie LeDuff's "No BS News Hour" podcast. Arena and his team were replaced after Nessel took office this year.

In annoucing the change of course Thursday, prosecutors now handling the case voiced "grave concerns about the investigative approach and legal theories embraced by" lawyers appointed by then-Attorney General Bill Schuette to handle the matter, "particularly regarding the pursuit of evidence."

Arena said he operated the investigation by the book and was puzzled why the new team had concerns about the evidence-gathering process and the review of evidence.

"I have no idea what they're talking about," he said.

He sees the dropping of charges as a slap in the face to him, special prosecutor Todd Flood, a private attorney, and Schuette, who lost his bid in 2018 for governor.

"My reputation, Todd Flood's reputation, Bill Schuette's reputation; It doesn't matter. None of that crap matters. Yeah, does it piss me off?, Yeah. I don't want my kids to read this crap in the paper," said Arena, who headed the Detroit FBI from 2005-12 and enjoyed a solid reputation inside the bureau.

Despite speculation that then-Attorney General Bill Schuette used the probe as a political prop for his run for governor, Arena said politics never influenced investigators.

"Throughout the investigation Bill never told us to do or not to do anytthing. He never told us anybody was off limits or we were targeting anybody. We just did things the way you're supposed to do it, by the book.

"If somene tried to push something political, I would not have allowed it," he said.